Method of forming cartons



A ril 15, 195

GUYER METHOD OF FORMING CARTONS Filed March 12, 1953 I INVENTOR 20vReyna/d5 Gaye/5' W1 mam 6 A RNEY United States Patent O METHOD OFFORMING CARTONS Reynolds Guyer, St. Paul, Minn, assignor to WaldorfPaper Products Company, St. Paul, Minn, a corpora tion of MinnesotaApplication March 12, 1953, Serial No. 341,998

2 Claims. (Cl. 9336.8)

This invention relates to an improvement in method of forming cartonsand deals particularly with the manner of folding cartons of aparticular type.

Cartons have previously been produced having what is known as a tearcorner structure. In other words, the slits which separate theindividual flaps of the carton do not extend completely to the fold lineextending around the cartons ends. As a result when these carton flapsare folded down into carton closing position, the carton stock tears fora short distance forming a web which acts as a seal at the corner of thecarton. The structure is particularly effective where a cut score is cutpartially through the outer surface of the carton extending from the endof the slit to the line of fold so that only the inner surface or linerstock is torn away.

While cartons of this type have been found effective for their desiredpurpose, diificulty has been found in folding the flaps into sealingposition and properly tearing the stock. The depth of the cut scorevaries somewhat in different cartons and as a result the carton cornersdo not always tear properly. In many instances the carton stock tearsdirectly through the corner of the carton, thereby destroying theeffectiveness of the seal and preventing the formation of the small webwhich acts to seal the carton corners. The present invention resides inthe particular manner of folding such cartons which has resulted in moreelfective sealing than other arrangements.

An object of the present invention resides in the provision of foldingthe flaps of a carton of the type described which includes the steps offolding two opposed fiaps inwardly simultaneously with the outwardfolding of the remaining two flaps. When the flaps are folded in thisspecific manner, the carton stock tears away more effectively than wouldotherwise be the case and the proper formation of the web at each cornerof the carton is insured.

A feature of the present invention resides in providing a webbed cornercarton having webs torn away from each corner of the carton and inproducing these webs by folding two opposed flaps downwardly into acommon plane while at the same time moving the remaining flaps outwardlyso as to pull the paper at substantially right angles. This action tendsto pull the inner portion of the paper stock away from the remainderthereof at the corners, this right angle pulling strain beingsubstantially more effective than doubling the stock and pulling almostin the plane of the remaining upstanding flaps.

These and other objects and novel features of the invention will be moreclearly and fully set forth in the following specification and claims.

In the drawings forming a part of the specification:

Figure l is a diagrammatic view of a portion of the blank from which thecarton is constructed.

Figure 2 is a perspective view of the carton in partially foldedcondition.

Patented Apr. 15, 1958 ice Figure 3 is a perspective view of the cartonin a different stage of the closing operation.

Figure 4 is a perspective view of the sealed carton, a portion of thelayers of the closing flaps being cut away to show the interiorconstruction.

Figure 5 is a perspective view of a corner of the carton during thefolding action.

Figure 6 is a sectional view, the position of the section beingindicated by the line 66 of Figure 1.

The carton is not shown in its entirety, as both ends of the carton maybe similar or the bottom end of the carton may be or" somewhat differentstyle. In the closing operation, one end of each carton may be sealedover a mandrel and accordingly a better seal may be obtained than isusually possible at the last closed end of the carton.

The carton is shown as including front and rear panels 1t} and ill. andside wall panels 12 and 13. These panels are foldably connected togetherby parallel fold lines 1d, 15, and 16. A glue flap 17 is foldablyconnected to one end panel of the series such as the panel 10 by a foldline 19.

Closing flaps 20, 21 are hingedly connected to two of the panels 12 andalong a common fold line 22. These flaps 2d and 21 are arranged to foldinto a common plane from opposite sides of the carton. A third closingflap 23 is hingedly connected to the panel 10 along the fold line 22. Afourth closing flap 24 is hingedly connected along the fold line 22 tothe wall panel 11. A short extension 25 is foldably connected to theglue flap 1']. When the glue flap 17 is secured to the side wall 13, thefiap extension 25 is foldably connected to the surface of the closingflap 21.

The various closing flaps are separated by slits'which do not extendentirely to the fold line 22. In other words, the slit 26 which isbetween the closing flaps 20 and 23 terminates short of the fold line22; A cut'score extends from the end of the slit 26 to the fold line 22.As shown in Figure .6 of the drawings, the slit'26 which separates theflaps 22 and 23 terminates at a distance from the fold line 22 and thecut score 27 which communicates with the slit 26 cuts only partiallythrough the carton stock and connects the slit 26 to the fold line 22.

A similar arrangement is provided between each pair of adjacent flaps. Aslit 2% is provided between the flaps 2t) and 24 and this slit 29terminates short of the fold line 22 and is connected thereto by a cutscore similar to the cut score 27. A. slit 3% is provided between theclosing flaps 21 and 24 and this slit 30 also terminates short of thefold line and a cut score forms a continuation thereof.

The glue flap extension 25 is also separated from the adjoining closingflap 23 by a slit 31 which terminates short of the fold line 22. andwhich is connected thereto by a cut score. Thus all of the slits betweenall of the flaps terminate short of the fold line.

I have found that with this arrangement some diificulty is experiencedin folding the various flaps without tearing the paperboard along theline of the cut score or in alignment with the slits. When all of thefour flaps are in the same plane as the panel to which they are hingedand when t e two shorter panels are folded down into a common plane, thepaper forms a fold at each end of the shorter flaps and tends to tearoff along a line of the cut score. This destroys the usefulness of theconstruction as we desire to provide a web or gusset of paper at eachcorner of the carton. We have also found that if the shorter flaps areheld in vertical position and the wider flaps are folded upwardly into afiat condition, there is also a tendency to tear the paper along the cutscore. However, we have found that if the fold ing actions take placesimultaneously and the shorter or inner flaps are folded inwardlysimultaneously with the outward folding of the outer flaps, the cartonstock will tear and produce a generally triangular gusset.

Accordingly it is the object of the present invention to fold theshorter or narrower inner flaps downwardly and to simultaneously foldthe wider or outer flaps outwardly. This tends to tear the inner linerof the carton board away from the outer portion thereof to form agenerally triangular gusset at the carton corners, the inward folding ofthe shorter flap acting to create a pulling force against the innerliner which is at all times substantially at right angles to the widerflaps or substantially in the plane of the shorter flaps. This tearingaction continues until the portion torn away is of sufficient length toreach the edge of the shorter flap when these flaps are in coplanarrelation. In other words, the tearing action takes place through anangle of approximately forty-five degrees, the end of the torn portionbeing connected to the wider flaps along diagonal lines about forty-fivedegrees in angle from the fold line 22.

When the innermost flaps 20 and 21 are folded into a common plane andwhen the wider flaps 23 and 24 are also folded outwardly into the sameplane, a web of thin paper tape may be secured across the entire top ofthe carton, the marginal edges of the tape being anchored to the widerflaps 23 and 24. This particular construction is not a part of thepresent invention. However, the particular method of folding the flapsto accomplish the desired tearing action in the corners of the carton isan important part of the present invention.

After the carton has been folded into the position shown inFigure 3, theweb may be attached if it is so desired. Subsequently the shorter flap23 is folded to overlie the coplanar inner flaps 20 and '21 andthereafter the wider closing flap 24 is folded to extend entirely overthe remaining flaps. If the inner web is omitted, both the flaps 23 and24 may be of equal width as is usual in such cartons.

In accordance with the patent statutes, the principles of constructionand operation of the method of forming cartons has been described, andwhile it has been endeavored to set forth the best embodiment thereof,it

is desired to have it understood that these are only illustrativethereof and that obvious changes may be made within the scope of thefollowing claims without departing from the spirit of the presentinvention.

I claim:

1. A method of producing a tight sealed paper board carton from arectangular tubular carton blank having closing flaps foldably connectedto the carton walls, the flaps being separated by slits which terminateoutwardly of the fold lines connecting the flaps to the carton walls,the method consisting in folding two opposed closing flaps outwardly andsimultaneously folding the remaining opposed flaps inwardly, the inwardmovement of the remaining flaps maintaining the direction of pull atsubstantially right angles to the line of tear, the combined movement ofthe flaps tearing a portion of the thickness of the paperboard from theinner surfaces of the flaps folded outwardly, forming gussets at thecarton corners.

2. A method of producing a tight sealed paper board carton from arectangular tubular carton blank having closing flaps foldably connectedto the carton walls, the flaps being separated by slits which terminateoutwardly of the fold lines connecting the flaps to the carton walls,and having cut scores extending through the outer surface of the flapportions between the ends of the slits and the adjacent carton corners,the method consisting in folding two opposed flaps outwardly andsimultaneously folding the remaining opposed flaps inwardly, the inwardmovement of the remaining flaps maintaining the direction of pull atsubstantially right angles to the line of tear, the combined movement ofthe flaps creating a pulling action against the uncut portion of thepaperboard inwardly of the cut scores and pulling a portion of thethickness of the paperboard forming the outwardly folded flaps away fromthe remainder of the flaps to produce a gusset fold at each corner ofthe carton.

References Cited in the file of this patent UNITED STATES PATENTS2,485,235 Graf Oct. 19, 1949

